docs: def register(self, arguments=list()):
          """
          Register a target file with arguments (if required) to a event_control file
          which we want to be notified events.
          """
          target_name = self.target_name
          if target_name in ['memory.usage_in_bytes', 'memory.memsw.usage_in_bytes']:
              threshold = arguments[0]
              line = "%d %d %d\0" % (self.event_fd, self.target_fd, long(threshold))
          elif target_name in ['memory.pressure_level']:
              threshold = arguments[0]
              line = "%d %d %s\0" % (self.event_fd, self.target_fd, threshold)
          else:
              line = "%d %d\0" % (self.event_fd, self.target_fd)
          os.write(self.ec_fd, line)